In the field of regenerative medicine, the use of mesenchymal stem cells for treating tissues in the human body has been attracting attention.
Mesenchymal stem cells are contained in bone marrow aspirates, umbilical cord blood, peripheral blood, and the like, and are cells having a multipotency capable of differentiating into various types of cells, such as those in bones, cartilages, fat, heart, nerves, and liver. However, mesenchymal stem cells comprise, for example, about 0.05% of the total cells in bone marrow aspirates, while it is necessary to collect a large amount for direct clinical use. Such a direct clinical use is a heavy burden for the living body and, therefore, use of cells obtained by subculturing mesenchymal stem cells collected from living tissue is desirable.
Proliferation of mesenchymal stem cells to a desired amount by primary culturing and subculturing of a collected bone marrow aspirate is conventionally already known (Patent Literature 1).